Erythrocytometer



June 23, 1953 R. P. MOORE 76 ERYTI-IROCYTOMETER Filed June 7, 1950 2 125a J j 32 '24 2 24* 36 3 Fig 5 Robert R- Moore Patented June 23, 1953Robert P. Moore, HampdenQSydney, Va. Application June 7, 1950QSerialNo.166,667

This invention relates to an erythrocytometer, the primary object ofwhich is to permit rapid and easy measurement of the mean diameter ofred blood cells prepared as a smear on a microscope slide. novelextension of the principle that the diameter of concentric spectraproduced by'the passage of light from a point source through a film ofred blood cells is inversely proportional to the mean diameter of thered cells. 7

Although skilled hematologists can roughly estimate cell diameter bymicroscopic examination of a blood smear, there is a need in the art fora simple device by which the clinician in oflice and rural practice mayhave ready access to the advantage of such measurements, and to this endthe present novel erythrocytometer has been conceived and constructed.

Instruments previously devised for this purpose have, by nature oftheir-structure, been poorly adapted for use in ofliceand ruralpractice; for example, the heretofore known diffractometric directreading erythrocytometer'is too largeto carry in a handbag and tooexpen-l sive for general use outside of a laboratory. The diffractionerythrocytometer approaches the desired simplicity to some extent,but'is mechanically undesirable because two variable f actors enter intothe diffraction changes, thus making calibration a difficult procedure.The present device has been provided to avoid the undesirable featuresof both of these instruments.

The value of knowing the 'average red cell diameter is well known to thephysician. It is of great aid. in the morphological classification,diagnosis and treatment of anemias. For example, the most characteristicfeature of Addisons anemia is an increased mean corpuscular diameter,whereas other findings are less constant. Furthermore, the averagepractitioner is enabled to differentiate the macrocytic group of anemiaswhich are generally amenable to liver therapy from the more commonhypochromic anemias which respond generally to iron therapy. Therefore,the present device gives immediate information as to the generaldiagnosis and pursuit of treatment inthe more common anemias, which isnot ordinarily possible without the aid of laboratory service. Since theaverage physician, especially in rural areas, does not have easy accessto precise laboratory assistance, this instrument, because of itssimplicity and ease of operation, is of great value to the averagephysician.

These, together with various ancillary objects and features of theinvention which will later become apparent as the following descriptionproceeds, are attained by the device, a preferred embodiment of whichhas been illustrated, by way of example only, in the accompanyingdrawings, wherein;

The present device is based on a Claims.' 01. sa -44) Figure 1 is asectional view taken substantially on the plane of section line Il ofFigure 2;

Figure 2 is an elevational view of the lower end of the device as shownin Figure l;

Figure 3 is a sectional view taken substantially on the plane of sectionline (i -3 of'Figure 1;

Figure 4 is a fragmentary sectional view taken substantially on theplane of section line 44 of Figure 3;

Figure 5 is a perspective view of a detail of construction.

specific reference will now be made to the drawings. In the severalviews, in the accompanying drawings and in the following specification,similarreference characters indicate corresponding elements throughout.

The present erythrocytometer is fabricated of a light-tight box l0 whichis elongated and preferably rectangular, although other shapes may beemployed. The conventional microscope slide box has been employed. toadvantage and comprises a base member l2 connected to side members 14, afront wall 16, and a rear wall Ill. The

- upper free edges of the walls are provided with a peripheral recess 20for seating a removable lid 22 to provide a light-tight box and to allowfor access to the interior thereof. The side walls [4 are provided witha pair of transversely aligned, longitudinally spaced serrations or bars24 at the central portions thereof for receving microscope slides 26having blood smears or stains thereon. I Thus, the smeared slide 26 ismaintained at a constant position in the light-tight box between theends it and I8 thereof.

The rear end l8 of the box is provided with a viewing aperture 28,whereas the forward end I6 of the box is provided with a transverselyextending channel 30 for sliding receiving a bar 32 having slopinglongitudinal'sides 34 to retain the bar within the guide channel 30;Adjacent one end of the bar 32 is a relatively small aperture 36 havingan index 38 thereat, this aperture serving as a light receivingaperture. The guide channel 30 and the slidable bar 32 have beenprovided so that the light receiving aperture 36 can be adjustedtransversely of the light-tight box I0 to properly align the aperture 36with the blood'smear on the microscope slide 26.

The slidebar 32 is further provided with an elongated slot 40 adjacentthe light receiving,

aperture 36. A disk 42 is provided which is circular and through thecenter of which extends a headed pin 44 which in turn extends througha'suitable aperture 46 in the slide bar and also 3 on the slide bar andalso movable transversely with the slide bar.

The disk is provided with calibrations 50 in miora adjacent itsperipheral edge and is further provided with a series of apertures ofvariable transverse distance from the light receiving aperture 36. Thisseries of apertures may be in the form of a continuous slot in the shapeof an Archimedean spiral, or preferably, as shown in the drawings, of aseries of apertures 52 arranged in the form of an ArchimedeanspiraLtheapertures 52 being selectively positionable in front of the elongatedslot 40 of the slidable'bar 32, as shown clearly in Figures 2 and 3.Inasmuch as the slot 40 in the slide bar 32 is linear and the series ofapertures 52 or slot thru the rotatable disk 42 is arranged inan-Archimedean spiral, it will be seen that the transverse distancebetween the light receiving aperture 36 and the spiral slot or spirallyarranged apertures 52 may be varied with the rotation of the disk 42. Inproportion to the other box dimensions, the light apertures 36 and 52should be approximately to ,6 of an inch in diameter.

In practical operation, to examine blood, a thin unstained smearprepared on a microscope slide is placed in appropriately adjustedposition within the box l0 and the lid 22 replaced. When the forward end[6 is held up toward a suitable source of light, one observes, onlooking through the viewing aperture 28, a pair of adjacent halo-;pectra. One of the pair of halo-spectra is produced by light passingthrough the fixed aperture 36 and the other is produced by light passingthrough the movable aperture produced by means of positioning one of theapertures 52 in front of the slot 40. With a properly made smear, onesees that each spectrum has a large central zone of bright light, paleviolet in color, which is surrounded by a thin zone of pale yellowmerging into dark yellow, and then successive zones of red-brown andblue. A measurement is made by bringing these two halo-spectra into apredetermined position; namely, the tangential approximation of theinnermost dark yellow spectra. The value for the average diameter of thered blood cells is then read directly from the calibrations 50 upon thedisk coinciding with the index 38. In selecting a light source,oneshould preferably use a fluorescent type of bulb or any otherdiffused light which is sufliciently intense. As will be readilyunderstood by those skilled in the art, the sliding bar 32 is used tomove the light apertures to the best portion of the smear on themicroscope slide 25.

In view of the foregoing description taken in conjunction with theaccompanying drawings, it-

is believed that a clear understanding of the device will be quiteapparent to those skilled in this art. A more detailed description isaccordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shownand described a preferred embodiment of the invention, the same issusceptible to certain changes fully comprehended by the spirit of theinvention as herein described and within the scope of the appendedclaims.

Having described the invention, what'is claimed as new is:

1. An erythrocytometer comprising an elongated light-tight box having aremovable lid, one end of said box having a viewing aperture and theother end having a stationary light-receiving 4 aperture, means forretaining a blood-smeared slide in said box at a constant positionbetween said apertures, a linear slot in said other end terminatingadjacent said stationary aperture an index on said other endprox'imatesaid stationary aperture, and a disk having a graduated scalethereon rotatably mounted on said other end and including a plurality ofapertures arranged in slot.

-2. The combination of claim 1 wherein said other end of said boxincludes a transversely slidable member, said stationary aperture andsaid linear slot being provided in said slidable member and saidrotatable disk being mounted on said slidable member.

3. An erythrocytometer comprising an elongated substantially light tighthousing, a viewing aperture at one end of the housing, a transverse slotin the opposite end of the housing, a slide support intermediate theends of the housing for holding a blood smeared slide transversely inthe line of sight between said aperture and said slot, a bar overlyingsaid slot in light tight relation, a light receiving aperture in saidbar, said light receiving aperture being adjustable along said slot, aslot in said bar, a disk covering the slot in said bar, a spiral row ofapertures in said disk said apertures being selectively registrable withsaid slot in said bar.

4. An erythrocytometer comprising an elongated substantially light tighthousing, a viewing aperture at one end of the housing, a transverse slotin the opposite end of the housing, a slide support intermediate theends of the housing for holding a blood smeared slide transversely inthe line of sight between said aperture and said slot, a bar overlyingsaid slot in light tight relation, a light receiving aperture in saidbar, said light receiving aperture being adjustable along said slot, aslot in said bar, a disk covering the slot in said bar, a spiral row ofapertures in said disk, said apertures being selectively registrablewith said slot in said bar, a guide channel receiving said bar.

5. An erythrocytometer comprising a light tight box, a viewing apertureat one end of said box, a 'guide channel in the outer surface at theopposite end of the box, a slot in said end said slot communicating withsaid channel, a slide bar positioned in said channel, a fixed lightreceiving aperture in said bar, a longitudinalslot in said slide bar, adisk pivotally mounted on said slide bar, a row of apertures in saiddisk said apertures being arranged in spiral formation, said aperturesbeing selectively registrable with said slot in saidslide bar, a slideholder intermediate the ends of said box.

ROBERT P. MOORE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,974,522 Twyman et al Sept. 25,1934 2,322,128 Hausseret-alJune 15, 1943 2,498,030 Davis 'Feb. '21, I950 FGREIGN PATENTS NumberCountry Date 393,590 Great 'Britain June 6, 1933 903,872 France Feb. '5,1945

